有机肥及其施用方法对红壤磷吸附和解吸特征的影响

Adsorption and Desorption of Phosphate in Red Soil as Affected by Long-term Application of Organic Manure

利用有机肥大田定位试验，研究有机肥及其施用方法对水旱轮作的红壤磷吸附和解吸特征的影响．结果表明，施用有机肥料后土壤对磷的吸附量减少．吸附结合能常数Ｋ值下降，土壤对磷的亲和力减小．有机肥集中施于冬作的处理其吸附量小于分两季施用的处理．与吸附相反，吸附量大的处理其解吸量小，施用有机肥后，磷解吸量增加．有机肥集中施用的处理其解吸量高于分两季施用的处理．有机肥对低平衡浓度下的磷的解吸影响最大，即有机肥能促进高能吸附阶段的磷的解吸，由于这一阶段吸附的磷通常是很难解吸的，因此这对提高磷的有效性有极其重要的意义．

Field experiment was conducted to study the effect of long-term application of organic manure on the adsorption and desorption of phosphate in red soil. The results showed that the application of organic manure significantly decreased the adsorption and affinity of phosphate to red soil, and reduced K value. The soil in the treatments where organic manure was entirely applied to winter wheat adsorbed higher and desorbed more amount of phosphate than that in the treatments where organic manure was separately applied to winter wheat and rice.Contrarily to adsorption,the application of organic manure increased the desorption of phosphate.Organic manure had greater effect on the desorption of phosphate adsorbed in highcnergy phase which was difficult to be desorbed.This was an important if,echanism in the improvement of the phosphate availability by organic manure.